After the fall of France, there were still a substantial number of DB-7s which had not yet been delivered to the Armee de l'Air. On June 14, 1940 the United Kingdom agreed to take over the French DB-7 order, including the 16 aircraft that had been diverted to Belgium. The first diverted DB-7s began to arrive in Britain during August of 1940. They joined a few ex-Armee de l'Air DB-7s which had been flown to England by escaping French crews.
The early DB-7s powered by 1000 hp R-1830-SC3-G engines with single-stage superchargers were designated Boston I. When they arrived in Britain, the throttles of these French machines had to be modified so that their operation was reversed--being pushed forward to open rather than close as was the French fashion. A total of 130 DB-7s are listed on RAF rolls as Boston I, with RAF serials being AE457/AE472 (the 16 aircraft that had been released by France to Belgium), AX848/AX851, AX910/AX918, AX920/AX975, BB890/BB912, BD110/BD127, and DK274/DK277. Unfortunately, the final batch (DK274/DK277) arrived in damaged condition and had to be stricken off strength. These Boston Is were considered as being unsuitable for combat, and were restricted to training and other non-operational duties.
The ex-French contract DB-7s powered by the more-powerful 1100 hp R-1830-S3C4-G engines (first introduced on the 131st DB-7) equipped with two-speed superchargers were temporarily designated Boston II. RAF serials were AW392/AW414, BJ458/BJ501, BK882, BK883, BL227, BL228, BT460/BT465, BV203, DG554, and DG555. The French had originally intended to use the DB-7 as a short-range tactical attack aircraft. Consequently, these former French machines all had too short a range for the RAF to be able to use them as light bombers against German targets in Europe. It just so happened that the RAF was at that time in desperate need of an aircraft suitable for night fighting and intruder duties and which was also capable of carrying the heavy and cumbersome airborne interception radar that was available at the time. The Boston II had a good performance and had a large fuselage and appeared to fit the bill. The decision was made to modify most of the Boston II aircraft (as well as some Boston I aircraft which had been reengined) for night intruder and night fighting duties. These conversions were initially known as *Ranger* by the RAF, but were eventually named Havoc I.
The first Boston II -> Havoc I conversion was carried out by the Burtonwood Aircraft Repair Depot, Liverpool, during the winter of 1940/41. More than a hundred of these conversions were completed during the next few months. In all, 181 Boston aircraft were converted to Havoc I configuration. Included in this total were some Boston I aircraft which had been reengined. Serials were AW392/AW414, AX848, AX851, AX910 to AX918, AX921, AX923, AX924, AX930, AX936, AX974, AX975, some from AE457/AE472, BB891 to BB895, BB896 to BB904, BB907 to BB909, BB91, BB912, BD110 to BD127, BJ458 to BJ501, BK882, BK883, BL227, BL228, BT460 to BT465, BV203, DG554, and DG555.
There were two basic versions of the Havoc I, an Intruder version with a three-man crew, a glazed nose, five 0.30-inch machine guns, and 2400 pounds of bombs, and a Night Fighter version with an early AI Mk.IV radar, a two-man crew, and eight 0.30-inch machine guns.
The Intruder version of the Havoc I was painted all black and was equipped with flame-damping exhausts for night operations. It featured armor protection for its three crew members and it was equipped with four forward-firing 0.303-inch Browning machine guns in the lower part of the glazed fuselage nose, plus a single 0.303-inch Vickers flexible machine gun in the rear cockpit. A bomb load of up to 2400 pounds could be carried.
For pure night fighting duties, the Havoc I was fitted with a "solid" nose housing an additional four 0.303-inch guns and carrying an AI Mk.IV radar set. A crew of two was carried, a pilot in front and a radar operator sitting in the rear cockpit. There were no provisions for rear-defense machine guns or for bombs. Some Havoc I Night Fighters were fitted with a Boulton-Paul nose carrying a battery of no less than 12 0.303-inch machine guns.
The first of these Havoc Is entered service with No. 85 Squadron of the RAF on April 7, 1941. Havocs subsequently also served with Nos. 23 and 93 RAF Squadrons. First to go into combat with RAF units were the Havoc I (Intruders) of No. 23 Squadron, which entered service during the winter of 1940-41. The night intruders were extremely useful in their intended role, and caused considerable damage to many German targets on the Continent. Operating at night and at low altitude, they were difficult to intercept and carried a hefty punch with their 2000-pound bombload and battery of four 0.303-inch nose
Number 92 Squadron received twenty modified Havoc I (Pandora) intruder aircraft, the name "Pandora" being a code name for the Long Aerial Mine (LAM) which was an explosive charge towed by a 2000-foot length of cable stowed in the bomb bay of the Havoc. The LAM was trailed in the path of enemy aircraft in the hope of scoring a hit. Serials of Boston aircraft known to have been equipped with this device include AX913, BK883, BT465, and DG554. This device was not very successful, and only one victory was attributed to this system. No 92 Squadron was disbanded in November of 1941, and the "Pandora" Havocs were converted back to Intruder configurations.
Havoc I Turbinlite was the name given to a night fighter version which was modified to carry a 2.7 million candlepower Helmore/G.E.C. searchlight in the nose in addition to the AI radar. The system was the brainchild of Wing Commander W. Helmore, and was built by the General Electric Company. It was intended that this searchlight would operate in conjunction with the AI radar. The radar would be used to locate enemy night intruders, and the aircraft's radar controller would direct the pilot to close to within 3000 feet of the target. The spotlight would then illuminate the target so that accompanying fighters could attack it. Thirty-one such Turbinlite conversions were made. Serials of Havoc aircraft known to have been equipped with the Turbinlite included AX913, AX924, AX930, BB897, BB899, BB907/BB909, BD100, BD111, BD120, AW392, AW393, AW400, AW401, AW404, AW406, AW411, AW412, BJ460, BJ461, BJ467, BJ469, BJ470, and BK882.
Since the nose and the bomb bay were now full of equipment, the Turbinlite Havoc was unarmed and depended on accompanying fighters to destroy the targets which it was supposed to illuminate. Turbinlite Havocs were initially operated by No. 1422 Flight (Air Target Illumination Unit), which was formed at Heston in early 1941 to train crews and to supply specially-modified Havocs and Bostons. These aircraft were also operated by Nos 1451 to 1460 Flights (later re-numbered Nos 530 to 539 Squadrons. This mode of attack was not all that successful, since the glaring searchlight gave enemy defensive gunners something bright to fire at. By late 1942, the development of centimetric radar had made such techniques obsolete, and the last Turbinlite Havocs were withdrawn in January of 1943.
In 1940, the new Douglas bomber had also attracted the attention of the British Purchasing Commission, which was, like its French counterpart, touring various American aircraft factories in search of combat planes. The British Purchasing Commission was impressed with the DB-7, but wanted some changes which would better suit it to British requirements. The British version of the Douglas bomber was designated DB-7B. An initial order for 150 was placed on February 20, 1940, which was increased to 300 on April 17. Following the standard RAF practice of assigning popular names to their aircraft, the name *Boston* was assigned to the DB-7B. Roman numerals were used to designate different versions. However, by the time that deliveries of the DB-7B to Britain had started, the designations Boston I and II had previously been applied to DB-7 aircraft commandeered from French orders, and so the DB-7Bs were designated Boston III.
The first DB-7B flew on January 10, 1941. 541 were built between May and December of 1941. Serials were W8252 to W8401 and Z2155 to Z2304. In addition, one DB-7B (AH740) was delivered as a replacement for the DB-7A (AH430) which had crashed while under test in the USA.
The Boston III began to arrive in Britain in the spring of 1941. The Boston III was the first of the DB-7/A-20 series actually to operate with the RAF in its intended role of light bomber. They were supplied to Nos 88, 107, 226, and 342 Squadrons in the United Kingdom and with Nos 13, 14, 18, 55, and 114 Squadrons serving in the Middle East and later in Italy. They replaced the Blenheims previously operated by these units. The first raid against the enemy in occupied France took place on February 12, 1942. They took part in attacks on the German warships Scharnhorst, Prinz Eugen, and Gneisenau when they took part in the famous channel dash during Operation Cerberus.
However, many Boston III aircraft were modified to Turbinlite or Intruder configurations. The Boston III (Intruder) aircraft retained their transparent noses but were painted matte black, equipped with flame-damping exhausts, and fitted with a belly gun pack housing four 20-mm Hispano cannon which supplemented the standard Boston III armament. These operated from mid 1942-onwards with Nos 418 (RCAF) and 605 Squadrons. Serials of the DB-7Bs converted to Intruder configuration include W8256, W8262, W8264, W8266, W8268, W8278, W8281, W8283, W8284, W8290, W8292, Z2155, and Z2165. Boston III aircraft fitted with Turbinlites included W8257, W8265, W8275, W8276, and W8300.
W8274, W8277, W8316, W8328, W8341, W8352, W8366, W8369, W8393, W8396, Z2184, Z2214, and Z2270 were converted to Havoc N.F.II. W8401 and Z2189 converted to trainers. Z2200 was transferred to the USAAF.
The RAF also inherited the October 20, 1939 French contract for one hundred DB-7As powered by the more powerful 1600 hp fourteen-cylinder Wright R-2600-A5B Double Cyclone air-cooled radial. These DB-7As were taken over by the RAF and assigned the name Havoc II. Serials were AH430/AH529. The first one (AH430) crashed on a factory test flight, but was replaced by a later Boston III (AH740). The first DB-7A flew in August of 1940. They were all brought up to British DB-7B standards before being delivered. When they arrived in Britain, the Havoc IIs were all converted to night fighter configuration and fitted with a new Martin Baker-built unglazed nose housing twelve fixed forward-firing 0.303-inch Browning machine guns.
480 DB-73s had been ordered by France on May 18, 1940. France split the DB-73 order between two American companies, placing half of it with Boeing in Seattle and the rest with Douglas in Santa Monica. Under the original contract, the DB-73 was to have been basically similar to the DB-7B for the RAF, but was to be fitted with French equipment and instruments. However, none of these had been delivered by the time that France fell, and all the DB-73s ordered were completed to DB-7B standards and were delivered to Britain as Boston IIIs. When delivered to the RAF, the machines built by Boeing were serialed AL668/AL907 and the machines built by Douglas were serialed AL263/AL503. Four of the Douglas-built DB-73/Boston IIIs were converted to Turbinlite configuration, and 28 of the Boeing-built machines were delivered to the Soviet Union. Others (both Boeing and Douglas machines) were delivered to the Royal Australian Air Force.
Further A-20s delivered to Britain were through the mechanism of Lend-Lease. They were assigned the USAAF designation of A-20C and carried USAAF serial numbers. A-20Cs acquired by the RAF under Lend-Lease were designated Boston IIIA. They were basically similar to the USAAF A-20C, with the exception of the use of British equipment and armament. The Boston IIIA also had extended carburetor air intakes above the cowling to include tropical filters. Other Boston IIIAs were taken over in the field by the RAF, some of them retaining their original USAAF serial numbers, while others received new RAF serials. 808 A-20Cs were built at Douglas-Santa Monica (41-19088/19462 and 42-32951/33383) under Lend Lease Contract DA2, and 140 were built under Lend-Lease Contract DA934 by Boeing at its Seattle facility (41-19589 to 41-19728). 200 went to Britain as the Boston IIIA (BZ196 to BZ352, BZ355 to BZ378 and BZ381 to BZ399), while others were taken over by the RAF in the field from the USAAF, with some machines retaining their original USAAF serials and others being assigned new RAF serials (HK896, HK870, HK872 to HK879, HK912, HK918, HK923, HK924, HK934, HK960, HK962, HK964, HK967, HK969, HK970, HK972 and HK973).
Most of the RAF Boston III and IIIA aircraft never did reach Britain. Large numbers of them were diverted to the Soviet Union following the German attack on June 22, 1941. In addition, following the American entry into the war in December 1941, substantial numbers of Bostons destined for the RAF were requisitioned by the USAAF. Some 162 Douglas-built and 194 Boeing-built Bostons ended up being seized.
It was not until late 1942 that the deliveries of Bostons to Britain resumed. Later in 1942, enough Bostons became available to equip No 197 Squadron and in 1943 No 342 (Free French) Squadron was equipped with Bostons. RAF squadrons flying Boston IIIs took part in a number of spectacular low-level attacks against targets in occupied Europe, numerous daylight Circus operations, and flew smoke-laying sorties during the invasion of Europe on June 6, 1944.
169 A-20Js were delivered to the RAF as Boston IV. RAF serials were BZ400 to BZ568. The A-20J was the transparent-nosed version of the A-20J. The Boston IVs retained the same armament (including the twin-gun Martin dorsal turret) as the USAAF version. They were used by Nos 13, 55, 88 and 114 Squadrons. It entered RAF service in the summer of 1944. 90 A-20Ks delivered to the RAF as Boston Vs. RAF serials were BZ580 to BZ669.
Bostons also flew with Nos 13, 18, 55, and 114 Squadrons of the RAF serving in the Middle East and later in Italy. They also flew with No 12 and 24 Squadrons of the South African Air Force, which actually preceded the RAF Boston squadrons into the area. The SAAF squadrons distinguished themselves during raids known as "Boston Tea Parties" flown against enemy airfields in the Western Desert. The four RAF squadrons flew Boston IIIs, IIIAs, IVs and Vs in support of Allied operations in Tunisia, Sicily, and Italy. The four squadrons operated their Bostons until early 1946, when they were either disbanded or re-equipped with Mosquitoes.
Havocs also served with the Fleet Requirements Unit of the Fleet Air Arm, which operated BD121, BD122, and BL227 in 1940-41.
In 1944 and 1945, only Nos 88 and 342 Squadrons were still flying
Bostons, but in April of 1945 they were disbanded.